Sunday, January 29, 2012

A sticky end

One of the delights of gardening is its very seasonality, the way as gardeners we become attuned to the ebb and flow of the year.  In spring we relish the emergence of the daffodils, and we plan for the upcoming planting season for the vegetable garden.  In summer we glory in the harvest of our sub-tropical crops (capsicums, tomatoes, cucumbers), while in autumn we marvel at the glory of the changing colours of the leaves.   In winter … well, in winter we hibernate, pull out our plant catalogues and plan another growing season.
But there are other regular patterns too, ones that garden writers come to experience.  One of these concerns an unusual and interesting plant that seems to puzzle people about every seven years or so.  Late last year the enquiries started about it again.
People get in touch to ask about a strange plant they have in their garden that looks a bit like a flax on a stem, or perhaps some kind of Agave (if they know what that is!) that has grown a trunk, and then flowered with an enormous and odd looking inflorescence.  This flowering stem, with pale white flowers, then does another unusual trick – instead of setting seed it produces small bulbils that can easily be detached and will thrive if potted up. 
And when they get in touch I know that it is a flowering season for Furcraea parmentieri (formerly F bedinghausii) – and that might cause heartache for the gardeners who get in touch, but more about that in a second.
Furcraea parmentieri is a wonderfully dramatic plant with great architectural value, its handsome blue-grey foliage making it a popular garden plant in many parts of the temperate regions of the world. Although it comes from the arid regions of central southern Mexico at altitudes of 2500m-3000m and thrives in dry, free-draining poor soils it is hardy.  I have seen clumps of this plant used to great effect in the Dunedin Botanic Gardens.
But there is heartbreak for those who love this plant – like many of its relatives it is monocarpic – it flowers just once, in an amazingly dramatic fashion with a spike that can reach up to three metres, then goes into a rapid decline and dies.
The odd thing is that many of the plants in the region seem to die together.  I assume they have come been planted at the same time and whatever climatic trigger causes one plant to flower affects others raised at the same time.  A recent Times-Age photograph showed three plants along the front of a house, no doubt planted for their architectural value, now in full flower and about to die!
The last time we had a mass flowering of these plants I collected up some bulbils, and grew them on in the glasshouse, intending to plant them out.  I never actually got to put them in the garden, and gave most of them away, but I have two growing in large pots and they look very attractive.

Friday, January 27, 2012

In my newly replanted perennial garden a funny thing has happened.  Some of you might remember me writing this last year when I was writing about removing a lot of plants from this garden: “Another clump to go was a big patch of Crocosmia ‘Lucifer’, a plant that I have failed with - incredibly enough bearing in mind it is simply an improved Montbretia, one of the weediest of the South African bulbs.  The catalogue assured me it had wonderful foliage and ‘amazing heads of flame-red blooms’ but it has never flourished with us, perhaps being too crowded, but the flowers seem to fall to botrytis and the foliage gets very diseased looking, so out it came.”

Turns out I did not get rid of it all, and also that the clean out must have allowed better air circulation around it as it has been stunning this season, the foliage being nice and clean and the flowers, which are opening now, showing no sign of any disease. It looks just superb, although slightly at odds with the rest of the garden, as I planted a lot of light pink and blue flowers around it.

Other funny things have been happening too – lots and lots of white Gladiolus flowers have been appearing. It is one of the prime tenets of garden writing that Gladiolus most emphatically do not revert to white, despite many gardeners thinking they do.  Well, I have to say I have never planted any white Gladiolus in this (or any other) garden, so they are either reversions from other varieties, or they are very vigorous seedlings.  The stems on the (non-reverted) Gladiolus are most impressive – they reach up to two metres and when the flowers at the tip open, there is a little branch of new flowers appearing at the base of the stem as a little bonus.
It may be that strictly speaking these have not reverted to white, but they could have been seedlings from a non-white plant.  Either way, I have a patch of white Gladiolus where I once had coloured varieties.

Tigers for the summer

Mid to late summer can be a tricky time in the flower garden, with many perennials having had their main burst of flowering and now concentrating on growing a little to store some more fat to ensure a good flowering next season.  Thank God for those long term flowering plants like Dahlias and day lilies that seem to just keep on giving more months on end, and of course, for those annuals that have prolonged flowering periods.
Fortunately there are also some that flower at this time of the year, including a few very attractive bulbs with spectacular flowers.  I have a great love of the exuberant Central and South American show offs, the Jockeys Caps, or Tigridias to give them their proper name.  These are members of the vast Iris family (immediately noticeable by their arrangement for floral parts in threes) and are mainly forms of the one species, T. pavonia, although there are other species in cultivation, sometimes to be found on the lists of bulb specialists.  I have grown a number of these rarer species, but they are quite tender and it is difficult to over winter the bulbs.  They rot in the soil and are attacked by aphids if stored dry.
 The hardier garden hybrids are a different kettle of fish. As long as they are grown in well drained soil and in a sunny aspect, they will thrive in Wairarapa conditions and multiply nicely, without ever getting to be a nuisance.  The most commonly grown form is probably the bright red form, although a quick look around plant catalogues shows the pink form is the one most offered.  I like the red form, as it is a bright cherry red unseen in any true irises, but I think my favourite colour is probably yellow. 
You would think that with a name like Tigridia, these bulbs would have been named after tigers, and would accordingly have striped flowers.  Not so – they are solid coloured across the main part of the petals, but the central area of each flower is spotted and splotched with a co0ntrasting colour, usually deep red.  In the red flowered forms the central portion is yellow based, with red /maroon spots.  The most spectacularly different form I have grown is the species T. duranguense, a Mexican species with mauve flowers that are prominently mottled all over the flower.  There are many other species, mostly unavailable in New Zealand, to tempt the keen bulb collector.
These cheery flowers only last a day each, but they are carried in a long succession, with flowering lasting for over a month usually.  I find it pays to grow the different colours in different parts of the garden as the plants set seed very easily, and the red strain seems to swamp the other colours.  Tigridias are very easily raised from seed, and a range of colours would soon give rise to some interesting forms for the person interested in starting out plant breeding, as they flower from seed within two years.
There might be another reason for growing these plants – they are apparently delicious to eat! Luther Burbank, the great American plant fiddler and creator of the Burbank plum, the Plumcot and the Shasta Daisy, discovered that these lovely bulbs were edible.  He said: “When cooked like potatoes, or made into a stew, they constitute a really delicious vegetable.  To my taste the bulb of the tiger plant is at least the equal of any vegetable under cultivation. It is also highly nutritious. I am not sure that it has an equal among the vegetables of our gardens in its combination of nutritiousness and appetising flavour.

Sunday, January 08, 2012


The stars of the Christmas bouquet this year were the stems of luscious Penstemons, which I have scattered in various beds around the back yard, and with which I am totally enamoured. They are largely North American plants, and for our gardening purposes split into two different groups.  There are a number of more or less dwarf species which are very valuable for edging a border, or for an old fashioned rock garden. 
However, the more commonly found forms are the border perennials that are sometimes called the “queens of the summer border” much loved for the prolonged flowering season and their hardy reliability. They are very easy plants, at home in any soil as long as it is not too damp, and will thrive during the hotter summer months.  Many species are to be found in arid areas of North America, and Americans tend to think of them as wild flowers, which perhaps explains why the hybrids are more popular in Europe than they are in their own country.
One of the reasons I like these guys is that you can easily bulk them up yourself – they are very easily grown from autumn cuttings, grown under cover over winter and planted out in spring.  That allows you to be generous with the planting size you can go for, and believe me, a bed of ten or more of one variety looks absolutely stunning.
There are many, many varieties on the market, and I am not sure that they are all correctly named.  I have some catalogues where the owners are proudly stating they have the “true” form of a named variety, alongside that of other nurseries, where the same claim is made, and the plants are quite different.  It might be that the best thing is to see them in flower in your local garden centre and decide on that basis.
‘Blackbird’ is one variety there is some discussion about.  As I understand it, this has relatively small deep maroon flowers, held delicately on dark stems, making it a great cut flower.  It grows to just over a metre high, and will spread almost that wide after a few years.  But there is another ‘Blackbird’ being sold in New Zealand, and the “true” form, with flowers that are nearly as deep but are much fatter and are borne on a plant that is much stumpier in growth.
Another with slightly wiry stems is the glorious ‘Drinkstone’ which has rich reddish-pink bells drooping gently with large stems filled with colour.  When at its best, the large stems are covered with flower making this a great variety for picking.
One of the older varieties which have stood the test of time is the subtly coloured ‘Hidcote Pink’, named after the lovely English garden. It has medium sized flowers, pink with dark pink veins in the throat. It clothes its stems well with bloom and is a hardy reliable doer in the garden.
If you were picking a few Penstemon to grow with an eye for picking for the house you would make sure you had ‘Snow Storm’. It has pure white bells in heavy panicles on strong stems and is a fabulous addition to the border and is probably one of the best white flowering perennials for summer.  It is medium seized at about 80 cm, and has a bushy growth habit.
If showy plants are more you style, and you are a fan of falsetto singing or disco music you will not be able to resist ‘Maurice Gibbs’, with his cerise pink to red flowers with a bright white throat.  On the other hand, if you are feeling more sombre and sober you might want to go for the darkest Penstemon you can find.  In that case you will be looking out for ‘Raven’. As well as being one the darkest of all the varieties, it is also one of the showiest, with dusky, purple flowers that flare just enough to let you see a white striping on the throat.  It is not one of the huskiest growing of the Penstemon, but it is surely one of the prettiest.

Monday, January 02, 2012


The start of a new year is a good time to replenish the vegetable garden, although to most of us the thought of too much strenuous work in the days after Christmas is rather daunting. This season,  weather broke a few days after Christmas though, and those who had made the effort to replant were repaid with a few days’ showers to help water the new plants in.
I was not so well organised.  My gardening over the break consisted of harvesting various components of our festive fare, and helping my son and his partner exert a modicum of control over the wilderness that comprises their Wellington garden.
Still, the New Year’s weather might have dampened down enthusiasm for midnight frolics but it certainly left the garden spoil in great condition, and I was keen to get some leeks planted for the winter harvest.  I had some free ground from the small area where we had grown a token crop of Christmas potatoes, and although it is not really ideal soil for growing leeks, I managed to turn it over and went out seeking some leek plants.
I am usually keen to buy some, nice punnet-grown plants for the garden, but I think members of the broad onion family do better if planted from open-ground grown seedlings, so instead of popping along to my garden centre I shuffled into the supermarket and got a bundle of field grown leeks –they were bigger and huskier than anything I have ever seen grown in a punnet.
The first step in growing leeks is to carefully choose where to plant them.  They are not overly fussy about soil types but they do best on light soil that had been well manured for a previous crop, probably best a green leaved crop such as lettuce or cabbage.  They are best not grown in a patch that has previously grown a crop of new potatoes, as the soil will be too loose and friable – leeks do far better on quite firm soil – so I made sure I trampled over the soil to firm it up before I planted out.
If you like long white stems on your leeks you are probably going to have to try a trick or two at planting time. Using a thick dibber or trowel, make some holes about 15 cm deep and about 20cm apart, making sure the holes are vertical.  You then need to move the dibber or trowel from side to side so that the holes are slightly larger at the top and about 5 cm wide.
To prepare the plants, trim the roots until they are 2.5 cm long and also cut the tips off the leaves. The leeks should now be gently dropped into the holes, filling the holes with water.  The water will wash enough soil over the base of the plant to allow it to become established. When you are cultivating the soil around the plants later you will slowly fill the holes up.
You will need to keep a close eye on the young plants once they are placed out as they need to be kept well watered for the first few weeks. Once they have settled in you could give a side dressing of general fertiliser, or perhaps a weak liquid fertiliser. You well need to keep the weeds down, of course, and keep the soil well aerated to allow any natural water to seep in, plus to make better use of the irrigation you apply.
Once the plants are growing well you can start to build up soils around the base of the plants, aiding the blanching that will return a larger proportion of the vegetable as the sweet and subtle flavoured part of the leek, rather than the coarser and stronger green portion.
When you harvest them is up to your taste.  I am rather partial to baby leeks (I have a great recipe for fish fillet, herbs and baby leek casserole) so I pick some when they are still quite young.  I will let some grow larger but I think they are probably best when about 3cm through, perhaps a little more.  I am certainly no fan of those monsters you sometimes see at the vegetable shows, with stems about the thickness of a pick handle!